/*
 * Copyright (c) 2014-2022 Monix Contributors.
 * See the project homepage at: https://monix.io
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package monix.reactive.internal.consumers

import monix.execution.Callback
import monix.execution.{ Cancelable, Scheduler }
import monix.execution.cancelables.{ AssignableCancelable, SingleAssignCancelable }
import monix.reactive.{ Consumer, Observer }
import monix.reactive.observers.Subscriber
import scala.util.{ Failure, Success, Try }

/** Implementation for [[monix.reactive.Consumer.create]]. */
private[reactive] final class CreateConsumer[-In, +Out](
  f: (Scheduler, Cancelable, Callback[Throwable, Out]) => Observer[In]
) extends Consumer[In, Out] {

  def createSubscriber(cb: Callback[Throwable, Out], s: Scheduler): (Subscriber[In], AssignableCancelable) = {
    val conn = SingleAssignCancelable()

    Try(f(s, conn, cb)) match {
      case Failure(ex) =>
        Consumer.raiseError(ex).createSubscriber(cb, s)

      case Success(out) =>
        val sub = Subscriber(out, s)
        (sub, conn)
    }
  }
}
